Fractal wood burning, Lichtenberg figures

[Pat Barry]

I've seen some very interesting videos recently using high voltage for doing wood burning. The techniques rely on using a microwave oven transformer or some called an oil burner transformer to step up the 115 VAC line voltage to several thousand and then use high voltage probes to electrify the wood and cause lightening like wood burns. Does anyone here have experience with this and if so, what equipment have you used? I'm thinking this might be a fun (albeit potentially dangerous) thung to try.

[Pat Barry]

Here is a link to a YouTube video that shows an example of the process and results
YouTube https://youtu.be/17cqotU5vrQ

[Frank Pratt]

There are quite a number of people who thought it would be fun to try, but who are now dead.

[John K Jordan]

There are quite a number of people who thought it would be fun to try, but who are now dead.

https://www.woodturner.org/page/FractalBurning

https://www.woodworkingnetwork.com/n...ractal-burning

[Frank Pratt]

I've watched a lot of fractal burning videos and speaking as a master electrician, am horrified at what I've seen. Some of them show some reasonable precautions, most don't. They all should be have exhaustive explanations of the hazards, but that is usually limited to a few words. These people don't even know enough to have a clue what they are playing at.

Can it be done safely? Certainly it can, with the correct knowledge, equipment and procedures. I've not seen a single video that comes close to doing that.

[Pat Barry]

I've watched a lot of fractal burning videos and speaking as a master electrician, am horrified at what I've seen. Some of them show some reasonable precautions, most don't. They all should be have exhaustive explanations of the hazards, but that is usually limited to a few words. These people don't even know enough to have a clue what they are playing at.

Can it be done safely? Certainly it can, with the correct knowledge, equipment and procedures. I've not seen a single video that comes close to doing that.

What precautions would you recommend Frank? I'm particularly interested in the equipment side of this.

[Barry McFadden]

What precautions would you recommend Frank? I'm particularly interested in the equipment side of this.

If you want to go ahead with this I would recommend a purchased burner such as this https://conestogaworks.com/woodburners.html instead of jerry rigging one out of a microwave transformer. I briefly thought about giving fractial woodburning a try but decided, from a safety aspect, it just wasn't worth it. I've also read of major woodworking shows that will not accept any entries that have been done with this method..

[Grant Wilkinson]

I've done many of these, using my home made unit. As others have said, this is beyond dangerous if done incorrectly. As a starting point, stay far away from microwave transformers!! The amperage of these units is way to high. There is a commercially available unit available. Search on Conestoga. Mine is very similar to that one. I use an oil burner transformer, putting out high voltage, very low amperage. I used silicone wires rates to much higher than the current flowing through them, non-conductive probes and non-conductive clamps holding the probes. I stand on rubber mats and use high current rated gloves. I have two switches and a red warning light that all must be one before the current flows, and I trigger everything with a floor mounted on/off pedal.

I'm not saying that my method or anyone's is foolproof. When dealing with this amount of electricity, there is always a risk. I like the effect and am willing to take what I believe is an acceptable risk to achieve the results. However, as the links show, people have died using these things.

Here is a Youtube channel of a guy that does a lot of this. He has instructions on making units. https://www.youtube.com/channel/UC2y...dVj13IcRSBICHQ

Just an FYI, the AAW has banned all advertising of fractal units and will not permit any demonstrators to use them in sponsored or club presentations.

Edit. Barry and I seem to be typing at the same time, so there is some duplication between his post and mine.

[Pat Barry]

I understand the hazards of high voltage. My thought however is never trust the cables or probe handles. I would only use this in a remote mode wherein I would place the probes, stand back and use a switch to start and stop the process. I would never use hand held probes like I see on some of the videos. The microwave transformer method is as scary as the oil burner transformer method, although the voltages are much lower and therefore easier to insulate. The Congestoga equipment looks to be of the oil burner method.

[Myk Rian]

Having been in the furnace control trade for 35 yrs, I can attest to the use of a furnace ignition transformer. We used to play with them as apprentices, and had fun building Jacobs' ladders.
They were about 6kv at enough current to jump start up to .5", climbing to 2-3". Much safer than jury-rigging a MW xfrmr.
I have one in the garage I used as a stage prop one year.

[Eric Danstrom]

If you think how many people actual do fractal burning and consider the number of deaths it's got to be 1% to 5% death rate. I'd hate to come upon a dead fractal burner on fire as has been reported in the news. Ouch, that's gotta suck....

[Frank Pratt]

I understand the hazards of high voltage.

Everybody knows the hazards of high voltage. What most don't know is how it behaves at different voltages and how it will interact with what we normally think of as nonconductive surfaces.

[Barry McFadden]

It's not high voltage that is the killer... it's high current. You can have high voltage at very low current and not be harmed. No matter what the voltage is, low or high, if there is a high current associated with it that's where the danger is. Current as low as 200mA can be fatal.

[Grant Wilkinson]

Barry is correct. The oil burner transformer that I have is an Allanson. Secondary voltage is 10,000, but the current is 23mA. The microwave oven transformers are much lower voltage, but the current from some of them is 500mA. Neon sign transformers are similar in current to the oil burner ones.

[John K Jordan]

It's not high voltage that is the killer... it's high current. You can have high voltage at very low current and not be harmed. No matter what the voltage is, low or high, if there is a high current associated with it that's where the danger is. Current as low as 200mA can be fatal.

I agree - the high voltage by itself is not necessarily a problem but can enable the current to get into the body, "punch" through the skin even if the normal resistance is high from dry skin, in effect instantly reducing the resistance.

Some interesting reading: https://www.asc.ohio-state.edu/physi...l_current.html

An example of high voltage with low current - a small van de graff generator can easily generate 100,000+ volts but the current is only micro-amp. A friend and I built one years ago from a couple of stainless steel mixing bowls. For a party trick he demonstrated 11" sparks off the tip of his tongue. Hold a pin in your fingers and you will get no spark at all since the sharp point starts discharging the sphere at about 3' away. (You can see the spray of electrons at the pin point) But bring the flat of your hand or forearm near the charged sphere and you'll get a surprisingly painful (but harmless) shock at maybe 3-4 inches! But the thing couldn't light a match, let alone burn wood.